One problem related to engine noise has been reported for the 2008 Toyota Sienna. The most recently reported issues are listed below. Please also check out the statistics and reliability analysis of the 2008 Toyota Sienna based on all problems reported for the 2008 Sienna.
There was a pin hole puncture in the flexible material the oil cooler is made of. The result of this is that all the oil is forced out of the engine very quickly under high pressure. There was no warning until I heard engine noise. I had the van towed in and had the part replaced. The current factory authorized part is now made out of metal. The dealership then informed me that because of the failure of the part I would need a new engine. It will cost $10,000. I asked if there was anything I could have done differently to prevent this I was told no. My engine is still under warranty but the part that caused it is not. I realize parts break but this part is not a maintenance part and the expected outcome of its failure is engine replacement. This I have found from experienced auto people is common knowledge. I believe this is a defect that Toyota knows about and is willing to ignore by invoking their warranty as a reason to allow this to happen to unsuspecting owners. Oh, when I contacted Toyota for help with my $10,000 problem, they offered me dinner. At this point I own a $30,000 piece of junk ( I owe $20,000) none of this would have occurred if the part had been made out of metal originally or if there was some kind of safeguard built in to warn you of the potential problem. Unfortunately that is not the case. Please help.